Search for copper sulfides and sulfur chemistry in the Martian crust, based on geochemical data returned by NASA's MSL rover

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The element copper (Cu) is being detected (almost) continuously along the traverse (~18 km, since Aug 2012) of NASA’s MSL rover in Gale crater, Mars, but its quantification remains problematic. According to the current model, Cu abundances are < 50 ppm at most places, but may be ~20 times above background in selected areas. The goals of this project are: (a) develop a solid model of Cu quantification, (b) identify the Cu-hosting minerals (especially at targets with high Cu enrichment) and (c) infer their likely pathways of formation. This study shall focus on data returned by ChemCam, but will also use APXS, - two instruments onboard the rover that utilize LIBS (Laser Induced Breakdown Spectroscopy) and x-ray fluorescence, respectively, to infer chemical composition of Martian surface material. Goal (a) requires detailed analysis of the two ChemCam emission bands where the two strongest Cu emission lines (324.8 & 327.5 nm) overlap with lines of other elements (Ti in particular). In order to achieve goals (b-c) particular attention will be given to potential correlations of Cu with Ni, Zn, S as well as major chemical elements (Si, Al, Ca, Mg, Na, Ti, K, Mn) whose abundances are routinely determined on a daily basis over the mission. Elevated Cu might be correlated with sulfur (sulfide segregation?) and care will be given to prove or disprove that hypothesis. The high-level goals of this study are: (i) track down the fate of Cu at the surface and in the interior of Mars (in particular compare surface abundances to those in SNC meteorites and BSM [Bulk Silicate Mars]), (ii) illustrate a particular aspect of the Martian sulfur cycle (the most important geochemical cycle at the Martian surface over billions of years) and (iii) address the question if ore-forming processes known from Earth might have taken place on Mars (perhaps at much smaller rate and spatial scale than on Earth).